The present invention relates to a laser leveling device for emitting a laser beam in vertical or horizontal directions to scan and for providing a reference line or a reference plane.
Positioning of a partition in a building or of a fluorescent lamp mounted on a ceiling is performed according to a marking line drawn on the floor, and the position indicated by the marking line is determined by projecting the laser beam by a laser leveling device to ceiling surface, wall surface, etc.
Referring to FIG. 9, description will be given on a conventional type laser leveling device, in particular to a laser leveling device 1 for providing a vertical reference line and a vertical reference plane.
A laser leveling device 1 comprises a main unit 2, having a projection system, a control unit, a power supply, etc. incorporated in it, and a rotating unit 3 having a pentagonal prism, rotated around a rotation axis in horizontal direction, on the main unit 2. A laser beam emitted from the projection system in the main unit 2 is emitted in a direction toward the rotation axis and in a direction perpendicular to the rotation axis via the pentagonal prism. By rotating the pentagonal prism on the rotating unit 3, a vertical reference plane is formed. On the top surface of the main unit 2, a bubble tube 4 is arranged, and three legs 5 are mounted on the lower surface of the main unit 2. One of the legs serves as a leveling screw to perform leveling by the laser leveling device 1.
In the past, the operation to perform adequate positioning of the laser leveling device 1 has been carried out as follows:
The laser leveling device is divided into two types: a type, in which the rotating unit 3 itself is rotated, and a type, which is designed in waterproof construction and in which only a rotating portion inside the rotating unit 3 is rotated. In the former type, in which the rotating unit 3 itself is rotated, positioning of the laser leveling device is manually performed by the operator while rotating the rotating unit 3. In the latter type, which has a rotating portion incorporated in the rotating unit 3, the rotating portion cannot be rotated from outside. Therefore, a mechanism must be specially arranged, in which a rotating portion can be rotated mechanically from outside, or another mechanism must be provided, in which a rotating portion can be electrically rotated in normal or reverse directions at low speed by an electric switch.
In the operation for adequate positioning of the laser leveling device, in case it is the device of the type, in which the rotating unit itself is rotated, positioning marks 8 and 9, which coincide with each other when the laser beam 10 is emitted in vertical downward direction from the rotating unit 3, are marked on the main unit 2 and on the rotating portion of the rotating unit 3. The rotating unit 3 is manually rotated to make the positioning marks 8 and 9 coincide with each other so that the laser beam is emitted in vertical downward direction from the rotating unit 3. In case the irradiating point of the laser beam is aligned with a reference point on the floor, e.g. with the point of intersection of the marking lines 6 and 7, and the scanning direction of the laser beam is aligned with the marking line 6, and the rotating portion of the rotating unit 3 is rotated or is reciprocally rotated within a given angular range to align a locus of the laser beam with the marking line 6. In a type of the laser leveling device, in which the laser beam aligned with the rotation axis is emitted from the rotating unit 3, the positioning of the device is performed in such a manner that it is aligned with the point of intersection of the marking lines 6 and 7, and that the irradiation point of the laser beam emitted in the direction of the rotation axis is aligned with a reference point marked on an extension of the marking line 7.
Further, the same applies to a type, in which a rotating portion is provided inside the rotating unit 3. By switching operation, the rotating portion is properly rotated, the laser beam is irradiated in vertical downward direction, and the irradiation point is aligned with the reference point. Then, scanning direction of the laser beam is adjusted.
In the conventional type laser leveling device as described above, the adjusting operation must be done in two steps, i.e. a step to install the device at the reference position and a step to adjust the scanning direction after installing the device while moving the rotating portion. This involves complicated procedure and much working time. In the type of the device, in which the rotating portion is incorporated inside the rotating unit, the rotating portion cannot be rotated from outside. Thus, a mechanism must be provided, in which the rotating portion can be rotated mechanically or electrically in normal or reverse directions. This results in more complicated structure.